Client server systems are utilized in a variety of fields, ranging from large-scale systems in which the Internet is used to small-scale systems such as home LANs. Moreover, client server systems are actively used in business organizations. For example, in call center operations, a client server system that includes a voice server is used to record a history of dialogues with customers in a database. In this system, a dialogue with a customer is sent from a terminal (a client) for an operator to the voice server as voice data, the voice server converts the voice data to text data by voice recognition and sends the text data back to the client, and then the operator records the text data in the database.
In general, in the aforementioned client server systems, a load balancing technique is adopted so as to achieve a quick response to clients by improving the efficiency of processes in the systems. In general, load balancing is performed among servers. In load balancing among servers, a client server system is known in which a special unit for load balancing called a load balancer is provided between a plurality of servers and clients, and when a request has been sent from one of the clients, the load balancer selects an appropriate one of the servers and sends the request to the one of the servers (Patent Document 1).
Moreover, a system in which load balancing between a server and a client, other than load balancing among servers, is performed is known. For example, Patent Document 2 discloses a distributed processing system in which, when a connection request is received from a client, the CPU utilization of a server is checked, and when the CPU utilization is equal to or less than a predetermined value, a requested process is performed; and when the CPU utilization exceeds the predetermined value, an application program for performing the process is sent to the client, and the client performs the process. Moreover, Patent Document 3 discloses a distributed processing system in which a plurality of corresponding processing modules are provided in a server and a client, and the capabilities of the server and the client are compared to increase or decrease the number of processing modules to be performed in the server and the client in response to the result of the comparison. In this system, when the capability of the server is higher than that of the client, the number of processing modules to be performed in the server is increased, and when the capability of the client is higher than that of the server, the number of processing modules to be performed in the client is increased.    Patent Document 1: U.S. Pat. No. 6,779,017    Patent Document 2: U.S. Pat. No. 6,385,636    Patent Document 3: Japanese Patent Application Publication No. 2003-58519